LED projection lamps are also known as linear LED projection lamps and the like. As the LED projection lamps take the shape of strips, they are also known as LED line lamps. The LED projection lamps are mainly applied to field lighting and architectural decorative lighting and used for drawing the outlines of buildings and fields. As the LED projection lamps are widely used, the illumination direction of the LED projection lamps is required to be relatively flexible and often required to be adjusted according to field or real-time demands. If the LED projection lamps illuminate in different directions, the transmission path of the heat produced by the LED projection lamps will be certainly affected. More severely, the heat cannot be effectively dispersed in some directions and then excessive heat is accumulated. Therefore, the use reliability and the service life of the LED projection lamps may be affected. The heat dissipation capability of LED lamps is closely interrelated to stable operation, good quality and long service life of the LED lamps. As for LED projection lamps with high brightness requirement, as the heat produced is abundant and the illumination environment is inconstant, the heat dissipation performance of the LED projection lamps is even more crucial. Therefore, when the LED projection lamps illuminate at different angles and in different directions, how to realize optimal heat dissipation, how to not affect the heat dissipation performance in the illumination direction and how to realize uniform heat dissipation at any angle are technical problems necessary to be solved.